Figure 3
From: Radiative and nonradiative relaxation phenomena in hydrogen- and oxygen-terminated porous silicon
PL lifetime and integrated PL. (a) Arrhenius plot of the PL lifetime (on a semi-logarithmic scale) as a function of 1/T, at a photon energy of 2.03 eV (610 nm) for H-PSi (red circles) and O-PSi (black squares). The solid lines represent the best fit to the singlet-triplet model of Eq.2. (b) Arrhenius plot of the integrated PL. Inset shows the schematics of the excitonic two-level model with the upper excitonic singlet-triplet state and the ground (no exciton) state. The arrows represent the allowed (from the singlet) and the forbidden (from the triplet) optical transitions.